SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '859cffd4841c0df5eec3f495eab5b0a98694acbf021b9ce0f773293f8b2806ab' 
  AND token = 'mYkGxHRc5z9q2S9kknszyY+susDOR0NuHXhPi6DR2R4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}